The Red Jacket Formation of Southeastern Saskatchewan

L.K. Kreis

Kreis, L.K. (1988): The Red Jacket Formation of southeastern Saskatchewan; in Summary of Investigations 1988, Saskatchewan Geological Survey; Saskatchewan Energy and Mines, Miscellaneous Report 88-4.

This report describes a proposed redefinition of part of and upper member of the Gravelbourg Formation. The the Jurassic stratigraphy in southeastern Saskatchewan. Red Jacket Formation is named after a village near the The need for a redefinition has arisen because of difficul­ type section of the formation in the Tide Water North ties in attempting to extend stratigraphic picks of the Wapella Crown 14-22-15-1 (Lsd. 14-22-15-1W2M) well. Shaunavon Formation and upper member of the Gravel· bourg Formation from their type area in southwestern Included in this report is a description and discussion of Saskatchewan into southeastern Saskatchewan. the type section, as welt as the boundaries, distribution, lithology, age and correlation of the Red Jacket Forma­ In an attempt to redress these difficulties and in conform­ tion. A west to east cross-section showing correlation of ity with the North American Stratigraphic Code Jurassic strata between southwestern and southeastern (American Association of Petroleum Geologists, 1983, Saskatchewan is included in the accompanying map Article 23, Remark b), the author proposes the estab­ package. A description of core from the type section is lishment of a new stratigraphic unit in the southeast, the given in the Apppendix. This work is part of a broader Red Jacket Formation, which is separated by an ar­ study by the author of the oil-bearing Jurassic sand­ bitrary lithofacies cut-off from the Shaunavon Formation stones occurring at various levels in the Wapella - Moosomin area (Figure 2 and cross-sec­

T W NOR lH WAPELLA CR 14 22 15 1 tion in map package).

KB: 5 9 5 .6m 1. Stratigraphy

SP RES a) Type Section PERIOD The type section selected for the Red c R Jacket Formation is fully cored in the E T Tide Water North Wapella Crown well MANNVILLE G ROUP A 14-22-15-1 (Lsd. 14-22-15-1 W2M) c be­ E tween 2183.0 and 2452.0 ft. (665.4 and 0 u 747.4 m) below the Kelly Bushing s (K.B.). This well exhibits the typical lithologies and geophysical well log RIERDON FM. responses common to the Red Jacket Formation and is the only well possess­ BURROWS MEIR ing a continuous core through all of the formation, as well as contiguous strata. The well is illustrated as number 14 in

RED JACKET MOOSOMIN IVIB R the cross-section (in map package). J FORMAT ION u The cored interval in this well is il- R Iustrated in Figure 1. A s s ROCANVllL E MBA I Generally, recoveries of the 1.5 inch c diameter wireline core of the Red Jack­ L. GRAVELBOURG MBA et Formation in the Tide Water North Wapella Crown well is fair (approx. 60 to 80 percent) to good (approx. 80 to UPPER WATROUS MBR. 100 percent). However, a few intervals less than 10 ft. (3.0 m) in thickness demonstrate poorer recoveries. Unfor· tunately, the core is largely broken up M I due to repeated handling. Thus many SO URIS VALLEY FM s s. contacts are not well preserved or are completely absent, especially in inter· laminated and mudstone sections of Figure 1 - Type section for the Red Jacket Fonnation in the TW North Wapella the core. Crown 14-22-15-1 well, illustrating proposed stratigraphic subdivision and conKI interval .

Saskatchewan Geological Survey 211 The Red Jacket Formation has been divided into three The middle member is named the Moosomin Member members (Figure 1), all of them named after villages after the town in Twp. 14, Rge. 31W1. The Moosomin near their type section in the TW North Wapella Cr 14-22- Member is found in the type section for the Red Jacket 15-1 well. Formation between 2215.3 and 2360.0 ft. (675.2 and 719.3 m). The lower member is herein named the Rocanville Mem­ ber after the village in Twp. 16, Rge. 31W1. The Rocan­ The upper member is named the Burrows Member after ville Member occurs in the type section for the Red Jack­ the village in Twp. 15, Rge. 1W2. It occurs in the type et Formation between 2360.0 and 2410.0 ft.(719.3 and section for the Red Jacket Formation between 2183.0 734.6 m). and 2215.3 ft. (665.4 and 675.2 m).

Fl'G. 2 SG I RG ..n

1. ~ . : : : · I . I ~ ------·- .... ---~- J ...... · . .• . .I I ROCANVILLE .. ; FIELD ~-~-· j·+··~-:-:--__...,__.. _~---'4------· .r~. ·i ..; . ' . .

, '!_, __ _ . . · "NORTH WAPE ~ "''.,. : . LA ·:SJ ~ __.____ ! ·[ .---~?? .. 1-.-W~A.,....P_E_L_L:,:A~ ~--I_...E_!-_DT ;0 M00$0 IN AREA I 't---'r--\-----,--,--.~.. ---1-----,1-· ...., --;._. ~- f~, -~-.,.c:, ,~.' '"",.;--l • ' . ! I .' , 4:_i_:~:_:_:_:f >· 1 I ! ~ j . i~ . , ( :--~ , i RED. JACKq, FIELD I • T ···;---· - • :-J:·:~. r :-1 ,,: .,. • ! I

, 1

Figure 2 - Location map of the study area referred to in the text as the Wapella - Moosomin area.

212 Summary of Investigations 1988 Discordances and apparent changes in lithofacies in bourg" in southwestern Saskatchewan. He interpreted some portions of the Red Jacket Formation complicate this horizon as an unconformity and used this interpreta­ the correlation and recognition of these members. Dis­ tion to account for the variation in thickness of underly­ tinctive lithologic characteristics of these members are ing strata. A similar horizon was also identified in south­ best observed in core from the Wapella-Moosomin eastern Saskatchewan and southwestern Manitoba area of southeastern Saskatchewan (Figure 2). (Stott, 1955). Francis (1956), Klingspor (1958) and Kreis (1987) later adopted this "minor unconformity" or discon­ Further subdivision of each of these members into a formity, which occurs at the top of a weathered dolomite lower Unit A and an upper Unit B is at present restricted with abundant bluish chalcedonic chert, as the pick for to the Wapella - Moosomin area, where there is suffi­ the top of the Lower Gravelbourg in southeastern Sask­ cient well and core control. Subdivision using only log atchewan. It is noted that, in addition to bluish chalcec:1- responses is hampered by 1) the similarity of lithologies onic chert and weathered dolomite at this horizon, there between overlying and underlying units, 2) abrupt litho­ are commonly euhedral bipyramidal quartz crystals. facies changes, and 3) lateral variability in thickness as the result of numerous discordances which have locally The presence of chert and bipyramidal quartz has been thinned or completely removed individual units. interpreted as evidence for "vanished evaporites" (i.e., unpreserved evaporites) by Friedman (1980) in the Little Falls Dolostone (Late Cambrian) of Herkimer County, 2. Definition of the Lower and Upper New York. In this loca!ity, euhedral quartz crystals occur Boundaries in vugs in dolomite, sandstone and associated stromatolitic dolomites. This observation is noted in con­ a) Definition of the Base nection with chalcedonic chert and euhedral bipyramidal quartz crystals found at the apparent unconformity in The base of the Red Jacket Formation occurs in the southwestern and southeastern Saskatchewan. type section at 2410.0 ft . (734.6 m). Although this con­ tact is missing in core from the type section, it is found Detailed examination of drill cuttings and core makes it to be sharp in other cores in the Wapella - Moosomin apparent that the chalcedonic chert-bearing horizon in area. There appears to be a discontinuity between the southeastern Saskatchewan lies below a fossiliferous Lower Gravelbourg Member and the overlying Rocan­ olive-grey (5Y4/ 1) calcareous mudstone, which in turn is ville Member of the Red Jacket Formation. The pick on overlain by or interbedded with an oolitic, very light grey a geophysical log is readily made in the Wapella - (NB) to light olive-grey (SY6/1) limestone. This Moosomin area where porous sandstone of the Rocan­ mudstone and limestone unit is referred to in the cross­ ville Member of the Red Jacket Formation rests on the section (in map package) as Unit 81 of the lower limestone of the Lower Gravelbourg Member. This same Gravelbourg Member in southeastern Saskatchewan. contact however, is difficult to recognize in some wells The underlying dolomitic limestone unit with weathered to the south and west of this area due to a general lack dolomite, chalcedonic chert and sporadic euhedral of contrast in geophysical log responses with the under­ bipyramidal quartz at its top is referred to as Unit A1 of lying Lower Gravelbourg Member. the Lower Gravelbourg in southeastern Saskatchewan.

A similar lack of contrast is also locally present between Extensive geophysical log correlations appear to show the Lower and Upper Gravelbourg Members west of the that the mudstone and limestone of Unit B 1 in south­ arbitrary lithofacies boundary shown on the cross-sec­ eastern Saskatchewan correlate with what was tentative­ tion location map (in map package). For example, in ly called "Lower Gravelbourg" in southwestern Sas­ wells 9 and 10 on the cross-section, slightly sandy lime­ katchewan by earlier stratigraphers (e.g., Milner and stones of the Lower Gravelbourg Member exhibit scarce­ Blakslee, 1958). It would then appear that, although ly different SP/ Res responses from the overlying silty, there is general agreement on the boundary between slightly calcite-cemented sandstones of the Upper the Upper and Lower Gravelbourg Members in south­ Gravelbourg Member. The distinction between the western Saskatchewan, the top of the lower Gravel­ Lower and Upper Gravelbourg Members originally bourg Member in southeastern Saskatchewan has been proposed by Klingspor (1958, p. 34) has, in fact, never picked at a lower horizon, namely at the well-defined un­ been formalized in southwestern Saskatchewan. It is conformity at the top of Unit A 1. The acceptance of Unit only common usage which has brought about the sub­ B 1 as the top of the lower Gravelbourg Member in division of the Gravelbourg Formation into an upper southeastern Saskatchewan is a revision of an earlier and lower member. This lack of formalization has identification of the top of the Lower Gravelbourg Mem­ caused some confusion regarding the boundary be­ ber (Kreis, 1987). tween the Upper and Lower Members of the Gravel­ bourg Formation. The cross-section (in map package) shows the sug­ gested correlation and location of the apparent uncon­ An unconformity at or near the top of what has been ten­ formity at the top of Unit A1 in southeastern Saskat­ tatively called the "Lower Gravelbourg" by Milner and chewan (i.e., wells 9 to 14). Defined by bluish-grey chal­ Blakslee (1958) and other authors in southwestern Sas­ cedonic chert, weathered dolomite and sporadic katchewan appears to have a counterpart in euhedral bipyramidal quartz, it is interpreted to be the southeastern Saskatchewan. Vigrass (1952) noted the counterpart of the one illustrated in southwestern Sask­ presence of a horizon of abundant bluish chalcedonic atchewan (i.e., wells 1 to 3). In southwestern Saskat­ chert in what is currently regarded as the "Lower Gravel- chewan, the Lower Gravelbourg Member is subdivided

Saskatchewan Goo/ogica/ Surwy 213 by this apparent unconformity into a Unit A and a Unit In the type section for the Red Jacket Formation in the B. It is important to note that the presence of a cherty Tide Water North Wapella Crown 14-22-15-1 well (Lsd. dolomite with or without euhedral quartz has not been 14-22-15-1W2M), the calcite-cemented G,yphaea-bear­ observed in the intervening wells 4 to 8. A dashed line ing sandstone is present and the upper boundary for through these wells shows the suggested correlation be­ the Red Jacket Formation is taken to be at 2183 ft. tween units of the Lower Gravelbourg Member in south­ (665.4 m) (Figure 1). western and southeastern Saskatchewan.

The presence of a horizon defined by bluish-grey chal­ 3. Distribution cedonic chert, weathered dolomite and sporadic The Red Jacket Formation occurs in southeastern Sas­ euhedral bipyramidal quartz in both southwestern and katchewan, east of the previously described arbitrary cut­ southeastern Saskatchewan is deemed to reflect an inter­ off for the Shaunavon Formation and Upper Member of lude of evaporitic to subaerial conditions before the the Gravelbourg Formation. It extends eastward and return of marine conditions. The lack of evidence for an southward, respectively, to the Manitoba and North unconformity or evaporitic conditions in wells 4 to 8 may Dakota borders, and to the north as far as the eroded reflect the limit to which the Lower Gravelbourg sea edge of the Jurassic. The Red Jacket Formation was lar­ receded. gely removed by erosion in the north half of the Wapel­ la - Moosomin area during the Late Jurassic or Early b) Definition of the Top Cretaceous. The areal distribution of the Red Jacket For­ mation is illustrated on the map accompanying the The cross-section (in accompanying map package) cross-section (in map package). The extent to which its shows that the top of the Red Jacket Formation occurs subdivisions may be picked has not yet been defined. everywhere at the base of the calcareous mudstones of the Rierdon Formation. These mudstones commonly The Red Jacket Formation varies in thickness from zero overlie a fossiliferous calcite-cemented sandstone sub­ at its northern eroded edge (erosional edge of the Juras­ unit at the top of the Red Jacket Formation. Where this sic) to approximately 90 min the Wapella-Moosomin sandstone occurs, it is taken to be the uppermost por­ area. In the Tricent et al. Coothill well (Lsd. 6-14-14- tion of the uppermost unit, namely Unit B of the Bur­ 33W3M), the Red Jacket Formation is 88 m thick, due rows Member. This unit is generally composed of poorly to an apparent thickening of Unit A of the Rocanville sorted, very fine to fine-grained clear quartz sandstone. Member at the expense of Unit 81 of the Lower Gravel­ This sandstone is typically less than 1.5 m in thickness, bourg Member (Figure 3). Other locally thickened sec­ light olive-grey (5Y6/1) in colour, silty, argillaceous and tions have also been detected. calcite cemented, and contains minor amounts of pyrite and a trace of glauconite. However, it is the abundance of well-worn Gryphaea nebrascensis and other 4. Lithology pelecypod shell debris that characterizes this subunit. Christopher (1964) suggested that the presence of The Red Jacket Formation comprises a complex succes­ G. nebrascensis dates the sediment as Callovian in age, sion of sandstones, siltstones, mudstones and minor in which case this subunit would belong to the Rierdon carbonates. Sandstones and mudstones dominate, and Formation. are commonly interbedded and interlaminated. The Ap­ pendix gives a detailed core description of the type sec­ This calcite-cemented G,yphaea-bearing sandstone sub­ tion for the Red Jacket Formation. unit is interpreted as a lag deposit at the base of the overlying Rierdon Formation and is therefore thought to a) Roca nville Member lie unconformably on underlying strata. The presence of G. nebrascensis in this sandstone was not detected; Unit A: however, where this sandstone is not highly calcite-ce­ mented, it is indistinguishable on geophysical logs from In the Wapella Field area, the base of Unit A comprises underlying sandstones of the Red Jacket Formation. For a slightly silty sandstone which directly overlies the lime­ these reasons, this sandstone subunit is placed in the stones and calcareous mudstones of Unit 81 of the uppermost portion of Unit B of the Burrows Member at Lower Gravelbourg Member. In the type section log, the the top of the Red Jacket Formation. For a more basal contact of Unit A occurs at 2410 ft. (734.6 m). Un­ detailed discussion of the probable age and correlation fortunately, this contact is missing in the type section of this subunit, the reader is referred to Christopher core, but in other wells in the area it is found to be (1964, 1966) and Kreis (1987). sharp and locally erosional. Siltstone and interbeds of calcareous mudstone and argillaceous limestone also Where this uppermost sandstone subunit is not devel­ characterize Unit A of the Rocanville Member. oped, an interbedded and burrow-mottled sandstone and mudstone sequence is found which is difficult to dis­ tinguish on geophysical logs from the overlying Rierdon Unit B: Formation. In these instances, careful correlation with ad­ In the type section, the contact between Units A and B jacent wells exhibiting more obvious contacts on of the Rocanville Member is located at 2379.6 ft. geophysical logs, or use of available core, becomes (725.3 m). In the type section core, the overlying Unit B necessary. of the Rocanville Member consists of limey greenish·

Summa,y of Investigations 1988 214 s N

NORWICH ET Al COOTHILL 14 11 14 33. TRICENT ET Al COOTHILL 6 14 14 33

KB : 587.4m KB: 587.4m

R~ 650 RIERDON FM. m \ UNIT 8 c.:'!' BURROWS MBR.

UNIT B ,-.~·--=== c> MOOSOMIN MBR. UNI T A ?;-~- 700 RED JACKET '" t ; FORMATION UNI T B j ~..._ _~-___ ROCANVILLE MBR. UNIT.. (I

750 ~-~U=T 81~~-- --=:::::.::~'~=t:;;;~======750 -::-:__ --~ l . GRAVELBOURG J ..~ ~ MBR. ~ ? ~- UPPER WATROUS MBR. { ~ ~-=-= ' ~ --.:::=..

Figure 3 - North-south cross-section showing thickening in Unit A of the Rocanvi/16 Memb8r at the expense of the underlying Unit 81 of Lower GravelbOurg Member. grey (5GY6/ 1) mudstones which are typically dolomitic, siltstone, and minor stringers of limestone. The and minor interbeds of yellowish-grey (SYB/ 1) to light sandstones of Unit A vary in colour from light olive grey olive-grey (5Y6/ 1) and pale yellowish-brown (10YR6/2) (5Y6/1) to yellowish grey (SYB/1) and, where oil limestone. stained, pale yellowish brown (10A6/2) to dark yellowish brown (10YA4/2). These sandstones are generally In many other wells in the Wapella - Moosomin area, the moderately sorted, composed of very fine to fine­ mudstones and argillaceous limestones present in the grained, subangular to subrounded clear quartz, with upper half of Unit 8 are very hard, dolomitic and quite trace to locally abundant amounts of pyrite, mica and variegated near the top. Colours vary from pale reddish carbonaceous fragments. They can also be variably ce­ brown (10R5/4) to moderate yellowish brown (10YR5/4) mented. Iron-carbonate nodules up to 6 cm across have and greyish orange (10YR7 /4). also been observed in cores and large wood fragments have been intersected which span the entire cross-sec­ b) Moosomin Member tional surface of the core (i.e., 8 cm across). A discontinuity appears to exist between the Rocanville These sandstones are commonly interbedded and inter­ Member and the overlying Moosomin Member. This laminated with noncalcareous to weakly calcareous, contact is generally sharp and irregular, and the upper­ micaceous and carbonaceous olive-grey (5Y4/1) to most beds of Unit B of the Rocanville Member are typi­ medium grey (N5) mudstones. Perhaps the most distinc­ cally dolomitic and variegated in shades of red and tive characteristic of this unit is the occurrence of car­ orange, colours commonly associated with sediments bonaceous material and abundant, typically large (up to which have been subaerially exposed and subsequently 1 mm across) mica flakes. oxidized. The contact between Units A and B of the Moosomin The base of the Moosomin Member is found at Member appears to be gradational, and is placed at 2360.0 ft. (719.3 m) in the type section for the Red Jack­ 2257.0 ft. (687.9 m). The gradational nature of this con­ et Formation. tact and the similarity of lithologies between Units A and B make this subdivision difficult. Unit A: Unit B: Unit A of the Moosomin Member is invariably thicker than the overlying Unit B. It is characterized by a se­ The Unit B rocks comprise greenish-grey (5GY6/1) to quence dominated by sandstone, mudstone and locally dark greenish-grey (5GY4/1) mudstonea interbedded

Saskatchewan Geological Survey 215 with yellowish-grey (5Y8/ 1) to light greenish-grey The Gryphaea-bearing and poorly sorted sandstone sub­ (5GY8/1) sandstones. The sandstones tend to consist unit which commonly occurs at the top of the section is of very fine to fine-grained, subangular to subrounded included in Unit B of the Burrows Member as discussed clear quartz with varying silt and argillaceous content. earlier (in section 2b). Mica and pyrite are important accessory minerals in Unit B, as in Unit A, but carbonaceous fragments are relatively scarce. The sandstones in Unit B tend to con­ 5. Age and Correlation tain more cement than in Unit A. The mudstones are The Red Jacket Formation of southeastern Saskatchew­ also more commonly calcareous than in Unit A, in an is correlated with the Shaunavon Formation and the places grading vertically into argillaceous limestones. Upper Member of the Gravelbourg Formation in south­ The upper 10 to 15 m of Unit Bis generally charac­ western Saskatchewan (cross-section in map package). terized by a moderately to intensely bioturbated, inter­ The base of the Red Jacket Formation rests upon bedded and interlaminated sandstone/ mudstone se­ Unit B 1 of the Lower Gravelbourg in southeastern Sas­ quence. This bioturbation gives the interval a readily katchewan. The upper contact of the Red Jacket Forma­ recognizable burrow-mottled texture. locally, bioturba­ tion is taken to be the base of the overlying light olive­ tion has been so intense as to homogenize the sedi­ grey (5Y6/ 1), calcareous mudstones of the Rierdon For­ ment into sandy and virtually structureless rock. mation. Fauna such as the oyster G. nebrascensis and the ammonite Kepplerites date the Rierdon Formation c) Burrows Member as Callovian (Christopher, 1964).

Unit A: Imlay (1980) assigned a Bajocian age to the Gravel­ bourg Formation and the Lower Member of the The base of the Burrows Member is defined by a sharp Shaunavon Formation of southwestern Saskatchewan, irregular contact, suggestive of a discontinuity, which in and placed the Upper Shaunavon Member into the the type section occurs at 2215.3 ft. (675.2 m). At this Bathonian. The Red Jacket Formation may therefore be contact, olive-grey (5Y4/ 1) to medium grey (N5) sandy assigned a Bajocian/ Bathonian age. A possible excep­ mudstone or argillaceous sandstone commonly infills tion to this age is the Gryphaea-bearing sandstone of cracks in the underlying greenish-grey (5GY6/1) biotur­ the uppermost subunit of Unit B of the Burrows Member. bated sandstone/ mudstone of Unit B of the Moosomin Member. No flora or fauna which permit recognition of the Bajocian/ Bathonian boundary have been identified in Unit A is characterized by olive-grey (5Y4/1) to medium the Red Jacket Formation. A bioclastic limestone grey (NS) claystone and mudstone. Generally, the lower stringer capped with a coral rubble composed of well­ 10 to 40 cm is a silty, micaceous, locally argillaceous worn pieces of the coral Actinastrea occurs, however, in and calcareous, very fine grained, clear quartz sand­ the Moosomin Member of the Aberford Wapella 12A-34- stone, which in many places is interlaminated with 14-1 well (lsd. 12A-34-14-1W2M) at approximately micaceous siltstone and argillaceous laminae. Sporadic 724.7 m. Paterson (1968, p. 14) recorded a basal con­ interlaminations of micaceous and locally sandy glomerate of the Upper Shaunavon in southwestern Sas­ siltstone are common near the base and the top of the katchewan as containing derived Actinastrea, suggest­ unit. Numerous interlaminations of crushed thin-shelled ing that the Bajocian/ Bathonian boundary in this well pelecypods typically form pavements 1 to 2 mm thick might lie at the top of the limestone stringer. throughout the unit. Imlay (1980, p.68-69) showed the Shaunavon Formation Unit A is informally recognized by many workers in the of southwestern Saskatchewan to be equivalent to the Wapella-Moosomin area as the "Jurassic" or 'Shaun­ Bowes and Firemoon Limestone Members of the Piper avon· shale marker. Formation of northeastern Montana and northwestern North Dakota. He also correlated the Gravelbourg For­ Where this unit has not been removed by a Late Juras­ mation of southwestern Saskatchewan with the Tampico sic to Early Cretaceous erosional event, it provides an in­ Shale Member of the Piper Formation, and the Kline valuable and ubiquitous datum in the Red Jacket Forma­ Member of the Nessen Formation in northeastern Mon­ tion. tana and northwestern North Dakota. He also recog­ nized an unconformity in the Gravelbourg Formation of Unit B: southwestern Saskatchewan. In his correlation chart, Imlay (1980, p. 89-69) showed the Tampico Shale to be The upper contact of Unit A is gradational into the over­ equivalent to Gravelbourg strata above an apparent un­ lying Unit B of the Burrows Member. Unit B represents a conformity defined by chert pebbles (Figure 4). This return to the bioturbated, interbedded and interlaminat­ would appear to be t he same unconformity observed be­ ed, calcareous sandstone/ mudstone lithofacies, similar tween Units A and B of the Lower Gravelbourg Member to the upper 10 to 15 m of Unit B of the Moosomin in southwestern Saskatchewan, as was previously Member. In the type section, the contact between described (in section 2a). Units A and B of the Burrows Member is defined at 2203.5 ft. (671.6 m), while the top of Unit B occurs at Attempts at correlating the Red Jacket Formation with 2183.0 ft. (665.4 m). the Jurassic strata in Manitoba were unproductive. Al­ though Stott (1955, p. 6) showed the Shaunavon and

216 Summary of ln11estigations 1988 Gravelbourg Formations of Saskatchewan to be It also appears that Francis (1956) was correct in his equivalent to the Reston Formation of Manitoba, in suggestion that Stott (1955) picked the Reston Forma­ another correlation chart (p. 36) in the same report, he tion stratigraphically much higher in east-central Sas­ showed the Reston to be equivalent to the Gravelbourg katchewan than in southeastern Saskatchewan. Formation and the Lower Shaunavon Member (J-28) of the Shaunavon Formation. It would appear that inconsistencies in the definition and correlation of the Reston and Manitoba Formations in

N .E MON lANA A NO MAN ilOS A STACE NW NORTH OAK.OTA SW. SASK.O.TCHEWA~ S.E. SASK ATCHEWAN MANITOBA MANITOBA ( ArTCR 1Ml AV. 19'101 (ArTER IMlAY, 1980 1 1 T~IS PAPER I ( AFTeR STOTT. 1955p6) (AFTER S TOTT, t955pJ6 l (AF TER FRANCIS. 1956) >---'------4-~ ~ ~ - - -~+-~-·~- ---1f--- - -~--1--~- -~--t--~--~-1------:--::-; OVERLYING BEDS LOWER CRETACEOUS l OW E R CRETACEOUS LOWER CRE TACEOUS LOWER CRETACEOUS LOWER C~E'lACEOUS LOWER CRE TACEOUS

I I I ' [\ 1,-P-ORT-LAN- OIA~N ! I ~~LI \ \ KIMMERIOGIAN ~ :r 0 \ WASXAOA !;; t-._...__~-..J._.. ._ '\ SUCCESS,' "' \ FORMAll'ON ~ W...J::::::i::::t::::i:::::t, WASl(.ADA \ ~ OXFOROIAN SWIFT FOR M ATION ~ MASEFIELD RIEROON / FORMATION .. 0 f? :;,~NI < ,-.~~-1~~...... \ I .,....I .,.... 1 .,-- .,..., s3 ,_.,-..,...... ,.__...... _ ...._.,_4 CAL L OVIAH i ~:~mi~ z ";!: RIEROON RIERDON FORMATION MELITA FORMATION• AIEROON FORMATION FORMATION MELITA FORMAT ION• 0AT HONIAN ---?------BOWES MEMSEA i ~ UPPl: A ME.M9EA .i 1-F-IR-EM_ O_O_ N_l_lM_ f_S_T_O_NE--1 ~ ~ 1------; - :, 2 AE'O JACKET ll'.: MEMBER cC CC: LO WER M EMBER M ELITA FORM ATION• w ~ 0 FORMAl lON ~ >------, .. ~ C: TAMPICO SHALE l""-+------l AESlON FORMAltON ~ M E MBER ~ Z "'0 :, 0 RESTON FORMATION 0 i l-+-•. ,-. -.-0,-.-,.-,,-.-.-.-.,-.---,. : i~:J.:::.~[:::.I.1:::.1.::~~~li::::i::::i:::i:::i:::~ J 8AJ0CIAN ! !(,LINE MEMBER ~ ~ ! RESTON FORMATtON z 1------l ~ ~ ~ P~ARO SHAL E MEMB~R '--~------~O:..L.~-- - --"":+------+------+-~------i ~ z POE E VAPOR I TE. :,"' 0 AMARANTH AM AAANTH UPP ER M EM B ER MEMBER Cl: UPPER MEMBER UPPER ME MBER ~ FO~MAllON FORM AT IO N ...... ---1~-- ...... 1~ 3 \.-....L--?•-...... t z ~ T1,,, ,-..,...... ,. 1..-....---r--1--r--,--, ?~~I~ ..... lOA~C IAN z 0 !,1 f------1 Q .:: .,, ~ .. "'< .. « PLIENS8ACHIAtt ~ " ;: I? "I;' « w

~ SINEMUAIAN

H E TTAN GIAN

TRIASSIC f RIASS IC

Figure 4 - Stratigraphic correlation chart showing correlation of Red Jacket Formation with equivalent strata in conterminous areas. Note that the Melita and Reston Formations of Stott (1955, p. 6) are shown correlared with their /ithostratigraphic equivalents, but Stott believes their contact to be the Bathonian/ Callovian boundary.

Saskatchewan Geological Sur,;ey 217 Manitoba require resolution before their correlation with The grading scale for grain size of sandstone and Saskatchewan strata can be understood. This is mudstone is based on the Wentworth scale as follows: reflected in the correlation chart in Figure 4. Size Class Grain Diameter

6. References Very coarse grained 2 to 1 mm Coarse grained 1 American Association of Petroleum Geologists (1983): North to 0.5 mm American Stratigraphic Code; Bull. Am. Assoc. Petrol. Medium grained 0.5 to 0.25 mm Geol., V67, p841-875. Fine grained 0.25 to 0.125 mm Very fine grained 0.125 to 0.06 mm Christopher, J.E. (1964): The Middle Jurassic Shaunavon For­ Silt 0.06 to 0.004 mm mation of southwestern Saskatchewan; Sask. Dep. Miner. Clay 0.004 mm or less Resour., Rep. 95, 95p. The sorting classification used follows Payne (1942), -~-~ (1966): The Middle Jurassic Shaunavon Formation of southwestern Saskatchewan; Sask. Dep. Miner. who employed Wentworth size classes: Resour., Rep. 110, 308p. Well sorted 90 percent in 1 or 2 size classes Francis, D.R. (1956): Jurassic stratigraphy of the Williston Moderately sorted 90 percent in 3 or 4 size classes basin area; Sask. Dep. Miner. Resour., Rep. 18, 69p. Poorly sorted 90 percent in 5 or more size classes

Friedman, G.M. (1980): Dolomite is an evaporite mineral: The Geological Society of America (second printing, evidence from the rock record and from sea-marginal 1951) colour chart was used. ponds of the Red Sea; Soc. Econ. Paleon. Mineral., Spec. Publ. 28., p69-80. The term "laminae· in this report refers to layers less Imlay, R.W. (1980): Jurassic paleobiogeography of the conter­ than 1 cm in thickness, while "bed" refers to layers 1 cm minous United States in its continental setting; U. S. Geol. thick or greater. Surv., Prof. Pap. 1002, 134p. The following terms are used as a measure of mineral Klingspor, A.M. (1958): Jurassic stratigraphy of the and fossil abundance: Sweetgrass Arch-Manitoba section; in Goodman, A.J. (ed.), Jurassic and Carboniferous of Western Canada; Abundant greater than 10 percent Am. Assoc. Petrol. Geol., John Andrew Allen Mem. Vol. , p27-51. Minor 1 to 10 percent Trace less than 1 percent Kreis, L.K. (1987): Regional stratigraphic correlation and lithol­ ogy of the Jurassic, Wapella - Moosomin area, southeastern Saskatchewan; in Summary of Investigations Tide Water North Wapella Crown 14-22-15-1W2 1987, Sask. Geol. Surv., Misc. Rep. 87-4, p176-186. K.B: 1954 ft.(595.6 m) Milner, R.L. and Blakslee, G .W. (1958): Notes on the Jurassic of southwestern Saskatchewan; in Jurassic and Car­ boniferous of Western Canada; Am. Assoc. Petrol. Geol., Jurassic John Andrew Allan Mem. Vol., p65-84. Rierdon Formation top ...... 2120 ft. (646.2 m) Paterson, O.F. (1968): Jurassic megafossils of Saskatchewan Red Jacket Formation: with a note on Charophytes; Sask. Dep. Miner. Resour., Burrows Member top ...... 2183 ft . (665.4 m) Rep. 120, 135p. Moosomin Member top ...... 2214 ft. (67 4.8 m) Rocanville Member top ...... 2360 ft . (719.3 m) Payne, T.G. (1942) : Stratigraphical analysis and environmental reconstruction; Bull. Am. Assoc. Petrol. Geol., v26, p1697- Gravelbourg Formation: 1770. Lower Gravelbourg Member top . .. 241 O ft. (734.6 m) Watrous Formation: Stott, D.F. (1955): The Jurassic stratigraphy of Manitoba; Upper Watrous Member top ...... 2451 ft. (747.1 m) Manit. Dep. Mines Nat. Resour., Mines Br. Publ. 54-2. Mississippian Vigrass, L.W. (1952): Jurassic stratigraphy of Saskatchewan; unpubl. M.Sc. thesis, Univ. Sask. Souris Valley Formation top ...... 2572 ft. (783.9 m) 7. Appendix A Jurassic The following core description is for the type section of Rierdon Formation the Red Jacket Formation in the Tide Water North Wapella Crown 14-22-15-1 well, and includes strata im­ 2161.0-2183.0 Mudstone: light olive grey (5Y6/1), slab­ mediately above and below. (658.7-665.4) by parting, hard, highly calcareous, trace (Rec. 5.2 m) to minor amounts of disseminated pyrite, Intervals are given in feet below K.B., with the metric eq­ fossiliferous. A sparse assemblage of uivalent in parentheses on the line beneath. The figure belemnites, pelecypods (Gryphaea on the third line is the length of the interval in metres. nebrascensis), ostracodes and am-

218 Summary of Investigations 1988 monite shell fragments (Kepplerites?). Lo­ casional poorly preserved pelecypod cally, mudstone grades abruptly into shell. Local patches of minor amounts of claystone or siltstone beds up to 1.5 m very fine grained disseminated pyrite. Oc­ thick. casional sandy, calcite infilled, vertical Lower contact missing. fractures < 1 mm across. Lower contact gradational. Red Jacket Formation 2203.5-2215.3 Claystone: medium grey (NS) to olive Burrows Member (671 .6-675.2) grey (5Y4/1), hard, slabbyto flaggy part­ (Rec. 3.60 m) ing, locally slightly calcareous, oc- 2183.0-2189.0 Sandstone: light olive grey (5Y6/ 1), hard, casional parallel lamination of abundant (665.4-667.2) very fine to fine grained, subangular to pelecypod shells (possibly P. oblongota (Rec. 0.91 m) subrounded, clear quartz, poorly sorted, and P. simplex?). Occasional parallel calcite cemented, silty, slightly argil­ laminations of micaceous silt and locally laceous with minor amounts of very fine very fine grained clear quartz. Sandy, disseminated pyrite, a trace of glauconite olive grey (5Y4/1) mudstone from this in­ and abundant broken-up well-worn terval infills crack in the underlying Gryphaea nebrascensis and other greenish grey (5GY6/1) unit. unidentified pelecypod shells. Lower contact sharp. Lower contact not preserved. Moosomin Member 2189.0-2191 .0 Mudstone: greenish grey (SGY6/ 1) to (667.2-667.8) dark greenish grey (5GY4/1), hard, slab­ 2215.3-2226.9 Sandstone (80 percent) and Mudstone (Aec. 0.23 m) by parting, slightly calcareous to locally (675.2-678.8) (20 percent): moderately to intensely highly calcareous. Locally, abundant (Rec. 3.00 m) bioturbated, intermixed, mottled, light pelecypod molds (possibly Pleuromya greenish grey (5GY8/1) to greenish grey oblongata and P. simplex?). (5GY6/1 ). Sandstone is hard, compris­ Lower contact missing. ing, very fine to fine grained, subangular to subrounded clear quartz, locally abun­ 2191.0-2194.1 Mudstone: greenish grey (5GY6/ 1), hard, dant poorly preserved pelecypods and (667.8-668.8) slabby parting, slightly calcareous, swell­ trace amounts of mica and indeterminate (Rec. 0.92 m) ing clays, abundant molds of pelecypods fish fragments. Moderately sorted, argil­ and the occasional ostracode. Moderate­ laceous ( < 5 percent), silty ( < 5 percent) ly laminated with lenticular and parallel and well-cemented with calcite. Locally laminations of micaceous silt. abundant disseminated pyrite and oc­ Lower contact missing. casional nodules up to 2 cm across. Mudstone is greenish grey (5GY6/1), 2194.1-2196.5 Sandstone: bioturbated, mottled, hard, with slabby partings, locally abun­ (668.8-669.5) greenish grey (5GY6/ 1) to light olive dant pelecypods, high calcite content (Rec. 0. 73 m) grey (5Y6/ 1), hard, very fine to fine and up to 30 percent scattered, very fine grained, clear quartz, subangular to sub­ to fine-grained clear quartz. Patchy, pate rounded, moderately sorted, well ce­ yellowish-brown (10YR6/2) oil-staining mented with calcite, locally abundant over lower 30 cm. pelecypods. Locally abundant fine­ Lower contact gradational. grained disseminated pyrite. Very fine grained pyrite locally replaces pelecypod 2226.9-2231.0 Mudstone; intertaminated, greenish grey shells. Disturbed greenish grey (5GY6/1) (678.8-680.0) (5GY6/1) to dark greenish grey calcareous mudstone laminations com­ (Rec. 0.96 m) (SGY4/1), hard, slabby parting, cal- mon over lower third. careous. Laminated with micaceous Lower contact sharp. siltstone and silty, micaceous, very fine to fine-grained clear quartz sandstone 2196.5-2199.5 Mudstone: greenish grey (5GY6/ 1), hard, which locally exhibits pale yellowish­ (669.5-670.4) slabby parting, calcareous. In gradational brown (10YR6/2) oil-staining. (Rec. 0.80 m) contact with interlaminated, silty Lower contact missing. sandstone below. 2231 .0-2237.0 Mudstone: moderately bioturbated, mot­ 2199.5-2203.5 Sandstone: moderately to intensely (680.0-681.8) tied, yellowish grey (SY8/1) to greenish (670.4-671.6) bioturbated, highly interlaminated with (Rec. 1.47 m) grey (5GY6/ 1). Mudstone is hard, cal- (Rec. 1.20 m) mudstone and siltstone, light olive grey careous, with the occasional pelecypod (5Y6/ 1), moderately friable, moderately mold and traces of mica and fine-grained sorted, very fine grained, subangular, disseminated pyrite. Limestone bed from clear quartz, slightly calcareous, very silty approximately 2231.5 to 2232 .1 (up to 30 percent), minor amounts of (680.16 to 680.34 m). This limestone is mica, slightly argillaceous, trace of in­ very sandy and bioturbated over upper determinate bone fragments and oc- half, argillaceous, highly fossiliferous

Saskatchewan Geological Survey 219 (abundant pelecypod shells), peloidal (in­ ingty common over tower 3 metres. determinate carbonate grains < 1 mm Lower contact very gradational. across) with traces of unidentified bone fragments and patches of very fine 2292.0-2306.0 Sandstone (70 percent) and Mudstone grained disseminated pyrite <0.5 cm (698.6-702.9) (30 percent): interbedded and inter­ across. Mudstone is gradational with ar­ (Rec. 3.17 m) laminated. Sandstone ranges in color gillaceous, silty, micaceous, poorly from yellowish grey (5Y8/1) to light olive sorted, very fine grained sandstone over grey (5Y6/1) and dark yellowish brown lower 40 cm. (10YR4/2) where oil stained. The Lower contact missing. sandstone is generally friable but local calcite cemented zones up to 15 cm 2237.0-2243.5 Sandstone: yellowish grey (5Y8/1) to thick are observed. It is moderately (681.8-683.8) greenish grey (5GY6/1 ), hard, very fine sorted, containing very fine to fine­ (Rec. 1.43 m) to fine grained, subangular to sub-- grained, subangular to subrounded clear rounded, clear quartz, arglllaceous, silty, quartz, with locally abundant mica and trace of mica, trace of very fine grained carbonaceous fragments, and trace disseminated pyrite. Small-scale ripples amounts of pyrite. Abundant interlamina­ are observed at several intervals. tions of argillaceous, silty, micaceous Mudstone interbed from approximately and slightly carbonaceous sandstone 2239.5 to 2240.5 (682.6 to 682.9 m). The and occasionally olive grey (5Y4/1), mudstone is greenish grey (5GY6/1), sandy mudstone. Mudstone interbeds up slightly dolomitic and exhibits trace to 30 cm in thickness with abundant inter­ amounts of mica. laminations of silty, micaceous and car­ Lower contact of unit gradational. bonaceous, very fine grained clear quartz. The mudstone itself has as much 2243.5-2257.0 Mudstone: greenish grey (5GY6/1), hard, as 40 percent scattered, very fine grained (683.8-687.9) slabby parting, slightly calcareous to cal­ clear quartz. (Rec. 3.11 m) careous, trace of mica, trace of pyrite, Lower contact missing. trace of indeterminate fish(?) bone frag­ ments. Moderately bioturbated 2306.0-2317.0 Sandstone: yellowish grey (5Y8/1) with sandstone interbeds up to 40 cm thick (702.9-706.2) oil-stained patches of dark yellowish found between approximately 2247.0 and (Rec. 1.92 m) brown (10YR4/2). It is moderately friable, 2251.0 (684.9 and 686.1 m). Sandstone moderately to well sorted, composed of is composed of very fine to fine-grained very fine to fine-grained, subangular to clear quartz, is well cemented with cal­ subrounded clear quartz. There are trace cite, slightly argillaceous, silty (up to amounts of fine grained disseminated 30 percent) with trace amounts of pyrite, pyrite, mica and carbonaceous frag­ carbonaceous fragments and indeter­ ments. Locally, abundant interlaminations minate bone fragments. of argillaceous, silty, micaceous and car­ Lower contact gradational. bonaceous material. There are oc­ casional interbeds of sandy (up to 30 per­ 2257.0-2292.0 Sandstone (60 percent) and Mudstone cent very fine to fine grained, clear (687.9-698.6) (40 percent): interbedded and inter­ quartz) olive grey (5Y4/1) mudstone of (Rec. 6.40 m) laminated. Sandstone is yellowish grey less than 15 cm thickness. (5Y8/1) to dusky yellowish brown Lower contact missing. (10YR2/2) where oil stained. It is hard, moderately to poorly sorted, made up of 2317.0-2323.0 Sandstone: interlaminated, yellowish grey very fine to fine-grained, subangular to (706.2-708.1) (5Y8/1) to pale yellowish brown subrounded clear quartz. It is variably cal­ (Rec. 0.82 m) (10YR6/2) where oil stained. It is friable, cite cemented, silty (up to 30 percent) moderately to poorly sorted, containing and slightly argiltaceous ( < 3 percent), very fine to fine grained, subangular to with trace amounts of mica (flakes up to subrounded clear quartz with up to 1 mm thick), pyrite (nodules up to 3 mm 30 percent silt and minor quantities of across) and carbonaceous fragments. mica and carbonaceous fragments. Inter­ Sandstone is interlaminated and inter­ laminations of highly argillaceous, bedded with greenish-grey (5GY6/1) to micaceous and carbonaceous material olive-grey (5Y4/1) mudstone. The are common. mudstone is locally slightly calcareous, Lower contact missing. sandy (up to 30 percent very fine to fine­ grained clear quartz) and highly inter­ 2323.0-2349.0 Sandstone: yellowish grey (5Y8/1) to laminated with siltstone and silty, (708.1-716.0) pale yellowish brown (10YR6/2) where micaceous, very fine grained sandstone. (Rec. 4.58 m) oilstained. It is friable, moderately to well Mudstone interbeds range up to 90 cm sorted, composed of very fine to fine­ in thickness. Silty, micaceous and car­ grained, subangular to subrounded clear bonaceous laminations become increas- quartz. Generally it is silty (up to 20 per-

220 Summary of Investigations 1988 cent} with minor mica (flakes up to 1 mm grained, clear quartz). across} and trace amounts of fine­ Lower contact missing. grained disseminated pyrite and car­ bonaceous fragments. Locally, there are 2376.0-2378.4 Limestone: pale yellowish brown parallel to wavy interlaminations of slight­ (724.2-724.9) (10YR6/2), very hard, dolomitic, slightly ly argillaceous, micaceous and car­ (Rec. 0.74 m) argillaceous, trace to minor amounts of bonaceous material. Sandy, micaceous pyrite ( commonly in patches < 0.5 cm and carbonaceous mudstone interbeds across), traces of mica and scattered, measuring up to 1O cm thick are com­ very fine grained clear quartz. A few poor­ mon between approximately 2328.0 and ly preserved pelecypod shells and a 2338.0 (709.6 and 712.6 m). Locally, trace of indeterminate fish(?) bone frag­ these mudstones are interlaminated with ments are also present. silty, micaceous sandstone. Lower 40 cm Lower contact gradational. also interbedded with olive-grey (5Y4/1} mudstone up to 1O cm thick. 2378.4-2379.6 Mudstone: greenish grey (5GY6/1), hard, Lower contact missing. (724.9-725.3} slabby parting, becomes increasingly cal­ (Rec. 0.34 m} careous towards top, one large (4 cm 2349.0-2360.0 Sandstone: light olive grey (5Y6/ 1) to across) mold of pelecypod shell frag­ (716.0-719.3} dark yellowish brown (10YR4/2) in ment and trace amounts of indeterminate (Rec. 2.29 m) patchy oil-stained areas. Sandstone is bone fragments. Occasional laminations hard to moderately friable, well sorted, of silty, micaceous, very fine to fine composed of very fine to fine-grained, grained, subangular to subrounded, subangular to subrounded clear quartz clear quartz. with trace to minor amounts of mica and Lower contact poorly preserved. carbonaceous fragments (with the oc­ casional carbonaceous wood fragment 2379.6-2390.0 Sandstone: yellowish grey (5Y8/1) to up to 4 cm across). It is well cemented (725.3-728.5) dark yellowish brown (10YR4/2) in small with calcite over upper half, exhibiting (Rec. 1.89 m) ( < 3 cm) patches of oil staining. It is high angle planar (up to 20°) and current moderately friable, moderately to well ripple bedding. Laminations are defined sorted, containing fine-to medium­ by abundant mica (flakes up to 1 mm grained, subangular to subrounded, across) and organic detritus. slightly calcite-cemented clear quartz with Lower contact missing. trace to minor amounts of mica. Excel­ lent porosity in a well-sorted medium­ Rocanville Member grained interval between approximately 2383.0 and 2385.0 (726.3 and 727.0 m). 2360.0-2364.5 Mudstone: greenish grey (5GY6/1}, hard, Becomes siltier and finer grained above (719.3-720.7) slabby parting, moderately to locally high­ and below this interval. In gradational (Rec. 0.61 m) ly calcareous, sandy (up to 10 percent contact with underlying sandstone. scattered very fine to fine grained quartz). A 2 cm thick layer of calcite and 2390.0-2395.5 Sandstone and Siltstone: interlaminated, slightly oxidized, pyrite-cemented, poorly {728.5-730.1) interbedded, yellowish grey (5Y8/1} to sorted, fine-grained, subrounded clear (Rec. 1.07 m) light olive grey (5Y6/1 ), moderately hard. quartz sandstone occurs at the top of the Sandstone is moderately hard, moderate­ material recovered in this interval. This ly sorted, slightly calcite cemented, com­ sandstone layer is cemented with calcite posed of very fine grained, subangular and slightly oxidized pyrite. clear quartz with abundant silt (up to Lower contact is sharp and irregular. 50 percent), minor amounts of mica and an occasional pyrite nodule (up to 2364.5-2373.5 Limestone: yellowish grey (5Y8/ 1) to 1.5 cm across}. Abundant interlamina­ (720.7-723.4) light olive-grey (5Y6/1), very hard, tions and interbeds of sandy (up to (Rec. 2.29 m) dolomitic, highly argillaceous, slightly 30 percent very fine grained clear sandy (up to 5 percent scattered, very quartz), argillaceous siltstone over lower fine to fine grained clear quartz). Dark two-thirds. greenish-grey (5GY4/1) calcareous Lower contact gradationar. mudstone break between approximately 2367.5 and 2369.0 (721.6 and 722.1 m). 2395.5-2397.7 Mudstone: olive grey (5Y4/1), hard, slab­ Upper contact displays a 10 cm Jong ver­ (730.1-730.8) by parting, trace amounts of very fine tical fracture infilled with overlying (Rec. 0.55 m} grained disseminated pyrite, car- greenish grey (5GY6/1) mudstone. bonaceous fragments and indeterminate Lower contact sharp. bone fragments. Becomes calcareous over lower 15 cm. 2373.5-2376.0 Mudstone: greenish grey (5GY6/ 1), hard, Lower contact missing. (723.4-724.2) slabby parting, calcareous, sandy (up to (Rec. 0.46 m} 5 percent scattered, very fine to fine

Saskatchewan Geological Survey 221 2397.7·2400.0 Sandstone: white (N9) to yellowish grey matrix. This is immediately underlain by a (730.EH31.5) (5Y8/1 ), moderately friable, moderately 2 to 3 mm layer of fibrous calcite and (Rec. 0.65 m) calcite cemented, very fine grained, sub-- pyrite. angular, clear quartz, showing a trace of Lower contact of unit sharp. mica and locally abundant pyrite nodules (nodules up to 3 cm across present over 2410.7-2416.5 Limestone: light olive grey (5Y6/1), very lower half). Becomes increasingly inter· (734.8-736.6) hard, slightly argillaceous with trace laminated with very silty and slightly argil· (Rec. 1.77 m) amounts of mica and scattered, very fine laceous material over lower two-thirds. grained clear quartz. Becomes increasing­ Lower contact sharp. ly interlaminated over lower half with silty, slightly argillaceous laminae with abun­ 2400.0.2401.5 Mudstone: greenish grey (5GY6/1), hard, dant silt-sized disseminated pyrite. Lower (731.5·732.0) slabby parting, calcareous with a trace of contact sharply defined by a 0.5 cm (Rec. 0. 15 m) pyrite and very fine grained, scattered band of interlaminated, peloidal and quartz. sandy (up to 30 percent very fine to fine­ Lower contact of unit missing. grained clear quartz) mudstone with abundant disseminated pyrite and trace 2401.5·2403.0 Limestone: light olive grey (5Y6/1) to yel· amounts of mica and glauconite. (732.Q.732.4) lowish grey (5Y8/1), hard, dolomitic and (Rec. 0.34 m) argillaceous, with trace amounts of mica 2416.5-2431.5 Mudstone: olive grey (5Y4/1), hard, platy and very fine grained disseminated (736.6-7 41.1) to fissile parting, calcareous with abun­ pyrite. Grades up from a calcareous (Rec. 2.92 m) dant thin-shelled pelecypods <0.5 cm greenish.grey (5GY6/1) mudstone over across. Pelecypods so abundant as to lower 15 cm. form laminae < 1.0 mm thick which con­ Lower contact missing. sist entirely of crushed shells. An inter­ bed of olive grey (5Y4/1), highly fos­ 2403.Q.2405.2 Limestone: yellowish grey (5Y8/1), hard, siliferous (abundant pelecypods), sandy (732.4·733.1) dolomitic, slightly argillaceous, locally (up to 20 percent very fine grained clear (Rec. 0.82 m) abundant bean.shaped ostracodes and quartz) limestone with abundant very fine trace amounts of mica and pyrite. grained disseminated pyrite and a trace Lower contact of unit gradational. of mica and glauconite occurs between approximately 2421.5 and 2422.0 2405.2·2406.9 Siltstone: greenish grey (5GY4/1), hard, (738.1 and 738.2 m). (733.1 · 733.6) slabby parting, argillaceous, minor to lo­ Lower contact sharp, defined by a 10 cm (Rec. 0.52 m) cally abundant mica and sandy (up to band of highly fossiliferous (pelecypod 30 percent very fine grained clear quartz). shell hash), glauconitic, peloidal, pyritic Lower contact gradational. and sandy (up to 1O percent very fine to fine grained clear quartz) mudstone at 2406.9-2410.0 Sandstone: interlaminated, yellowish grey base. (733.6-734.6) (5Y8/1), moderately hard and moderate· (Rec. 0.91 m) ly to poorly sorted. Consists of very fine 2431.5-2432.2 Limestone: light olive grey (5Y6/1), very grained, subangular clear quartz and is (741.1-741.32) hard and massive. Occasional vertical argillaceous, very silty (locally up to (Rec. 0.22 m) hairline fracture lined with very fine 40 percent) with minor to abundant mica grained pyrite. Lower contact sharp and and a trace of carbonaceous fragments irregular, defined by a 1.5 cm thick band over lower half. Grades into a siltstone of calcite- and pyrite-cemented, fine­ over lower 30 cm. grained argillaceous sandstone at the Lower contact missing. top of the underlying mudstone.

Lower Gravelbourg 2432.2-2434.0 Mudstone: light olive grey (5Y6/1), hard, (741.1-741.9) silty to locally sandy (up to 40 percent 2410.0·2410.7 Limestone: olive grey (5Y4/1), very hard. (Rec. 0.61 m) very fine grained clear quartz) with minor (734.6·734.8) This limestone is dominated by ovate to very fine grained disseminated pyrite and (Rec. 0.20 m) subspherical peloids up to 2 mm in trace amounts of mica and glauconite. length and 1 mm across. The peloids Lower contact of unit missing. contain significant amounts of silt-sized pyrite. The limestone matrix is slightly ar· 2434.0-2437.0 Sandstone: light olive grey (5Y6/1), hard gillaceous with minor pyrite and a trace (742.2-742.B) and moderately sorted. lt consists of very of mica. The uppermost 1.5 cm interval (Rec. 0.55 m) fine grained, subangular to subrounded contains calcareous, olive·grey (5Y4/1) clear quartz and is calcite cemented. Has mudstone and rounded, medium- to minor amounts of mica, very fine grained coarse-grained olive-black (5Y2/1) car­ disseminated pyrite (occasional patch bonate grains (peloids), silt (approximate­ < 0.5 cm across) and a trace of car­ ly 20 percent) and trace amounts of bonaceous fragments. It becomes in­ glauconite in an olive-grey (5Y4/1) creasingly argillaceous and silty towards

222 Summa,y of Investigations 1988 base. cent), minor mica, minor to locally abun­ Lower contact appears gradational. dant glauconite and pyrite, minor sub­ rounded very pale orange (10YRB/2) car­ 2437.0-2440.0 Mudstone: greenish grey (5GY6/1), hard, bonate fragments and trace to minor (742.8-743.7) slabby parting, moderately calcareous, amounts of greyish blue (5P85/ 2) to (Rec. 0.46 m) sandy (up to 30 percent very fine to fine dusky blue (5PB3/2) subrounded to grained clear quartz), with minor mica rounded chalcedonic chert nodules up to and trace amounts of carbonaceous frag­ 3 mm across. ments and disseminated pyrite. Lower contact of unit sharp and irregular. Lower contact missing. Upper Watrous Member 2440.0-2444.0 Siltstone: light olive grey (5Y6/ 1), hard, (743.7-744.9) calcareous, argillaceous with traces of 2452.0-2459.0 Dolomite and Anhydrite: interbedded. (Rec. 1.07 m) mica and pyrite. Calcareous, greenish- (747.4-749.5) Dolomite is very pale orange (10YR8/ 2) grey (5GY6/ 1) mudstone break between (Rec. 0.31 m) to light olive grey (5Y6/ 1), while the an- approximately 2441.0 and 2441.5 hydrite is light bluish grey (587 / 1) to light (744.0 and 744.2 m). grey (N7). Dolomite is massive, brec­ Lower contact of unit gradational. ciated, with fractures infilled by gypsum. lnterbeds consisting of light bluish-grey 2444.0-2451.5 Mudstone: light olive grey (5GY6/1), (587 / 1) to light grey (N7) anhydrite inter­ (744.9-747.2) hard, flaggy parting, highly calcareous mixed with greyish-blue (5P85/) to dusky (Rec. 0.91 m) (approaching limestone composition). blue (5PB3/ 2) chalcedonic chert. Locally Lower contact of unit not preserved. euhedral, bipyramidal quartz crystals and chalcedonic chert nodules occur as ap­ 2451 .5-2452.0 Sandstone: greenish grey (5GY6/1), parent void-fill in the dolomite. (747.2-747.4) moderately hard, moderately to poorly Very poor recovery. (Rec. 0.23 m) sorted, very fine to fine grained, clear quartz, argillaceous, silty (up to 30 per-

Saskatchewan Geological Survey 223